CIU, also referred to as chronic spontaneous urticaria (CSU) outside the US, is a skin condition characterized by red, swollen, itchy hives on the skin and is diagnosed when hives spontaneously present and reoccur for more than six weeks.

Angioedema, or swelling of the deep layers of skin, is common in patients with CIU. At any given time, the prevalence of CIU is approximately 0.5 percent-to-one percent worldwide. Currently, H1 antihistamines are the only approved therapy for patients suffering from CIU.

"We are pleased with the results of the Asteria II study, as people with chronic idiopathic urticaria unresponsive to H1 antihistamines need new treatment options," said Dr Hal Barron, chief medical officer and head of global product development, Genentech. "We look forward to sharing the results of two additional phase III omalizumab CIU studies at upcoming medical meetings this year."